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Biomedical subjects

S A Danner

Publications and source records attributed to S A Danner.

At least 55 records · Page 3Linked to original sources
PubMed1998

Mycobacterium xenopi in HIV-infected patients: an emerging pathogen.

BACKGROUND: Mycobacterium xenopi is associated with pulmonary disease in patients with loss of local or general host defence. OBJECTIVES: To determine the occurrence of M. xenopi in our hospital during 1987-1992 and 1993-1996, as well as the association of M. xenopi with HIV infection in 1993-1996; to evaluate the clinical significance of M. xenopi in HIV-seropositive patients. DESIGN: Retrospective review of charts and classification of patients based on earlier definitions derived from the American Thoracic Society. SETTING: Tertiary hospital. PATIENTS: Patients with a positive isolate of M. xenopi from January 1987 until December 1996. MAIN OUTCOME MEASURES: During 1993 1996, a significant increase in the number of patients with M. xenopi was found compared with 1987-1992. Of 25 patients, 22 were HIV-seropositive. RESULTS: The HIV-seropositive patients were classified as having definite (n = 5), probable (n = 9) and unlikely disease (n = 8) due to M. xenopi. Symptoms, median CD4 cell count, treatment and outcome did not differ between these groups. CONCLUSIONS: M. xenopi is an emerging pathogen, especially in HIV-infected patients. The criteria of the American Thoracic Society for disease due to non-tuberculous mycobacteria do not seem applicable to M. xenopi in HIV-infected patients. We suggest that two positive cultures of M. xenopi and no other likely cause of symptoms present should be considered the criteria for diagnosis of M. xenopi disease in HIV-infected patients.

Adult↗
PubMed1998

[AIDS: new developments. VI. HIV reservoirs during intensive antiretroviral treatment].

Treatment of human immunodeficiency virus (HIV) infected persons with potent antiretroviral combination therapy results in a strong decline of the viral load in the blood. Whether this effect is reached in all tissues and different infected cell types is an important question. There are several potential virus reservoirs. Lymphoid tissue constitutes the largest virus compartment. With potent, often protease inhibitor containing combinations the HIV-RNA decline in lymphoid tissue runs parallel to that in the blood. The central nervous tissue is a potentially important reservoir, because of the limited penetration of several antiretrovirals, especially protease inhibitors. A few short studies with different combinations showed a decline of the amount of virus in the cerebrospinal fluid. The risk of local resistance developing is not known. There are only few studies of the effects of potent anti-HIV therapy on semen but prostate and testis tissue do not appear inaccessible to treatment. The reservoir of latently infected cells that cannot be reached by the immune system or by the viral replication inhibiting therapy, can possibly be reached with immune stimulating agents. This will cause HIV replication and cell death, while the anti-HIV therapy will prevent further replication of the produced virions. This approach is still experimental, however.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Rate of HIV-1 decline following antiretroviral therapy is related to viral load at baseline and drug regimen.

OBJECTIVES AND DESIGN: The dynamics uf viral decline following the initiation of antiretroviral treatment were studied in 29 HIV-1-infected patients participating in a two-arm trial comparing immediate (group A: ritonavir, zidovudine and lamivudine) and delayed (group B: ritonavir supplemented by zidovudine and lamivudine on day 21) triple therapy. Parameters underlying viral dynamics were estimated using mathematical models tailored to these treatment protocols. RESULTS: The decline in plasma HIV-1 density between day 0 and 21 was steeper in group A (-2.27+/- 0.46 log10) than group B (-1.87+/-0.56 log10). In a subset of patients amenable to full mathematical analysis, a short-lived productively infected cell compartment (producing approximately 97% of total virions) decayed with a half-life of 1.0-2.5 days, whereas a long-lived infected cell compartment decayed with a half-life of 18.8-32.8 days. Estimates for the time for the elimination of virus from these two cell populations ranged from 474 to 802 days. The rate of loss of productively infected CD4+ T cells was positively correlated with baseline viral load in group A and in the combined dataset. CONCLUSIONS: These results suggest that HIV-infected cell populations may have a faster turnover in patients with higher viral loads due to higher infection rate parameters, higher rates of virus production, or lower virus clearance rates.

Anti-HIV Agents↗
PubMed1998

Alternative multidrug regimen provides improved suppression of HIV-1 replication over triple therapy.

OBJECTIVE: To compare the viral suppression of two antiretroviral regimens using three drugs or five drugs. DESIGN: Two open-label studies using a three-drug (zidovudine, lamivudine and ritonavir) and a five-drug regimen (zidovudine, lamivudine, abacavir, indinavir and nevirapine) in study-drug-naive patients, except for one in the five-drug study. METHODS: Participants with > or = 10 000 HIV-1 RNA copies/ml in plasma at baseline were compared by means of Kaplan-Meier curves for time to < 50 copies/ml, as well as linear regression analysis for the first phase of decline using log-transformed copy numbers. RESULTS: The elimination rate constants for HIV-1 RNA in 15 participants of the three-drug study were compared with nine participants of the five-drug study. The level of < 50 copies/ml was reached earlier when using the five-drug than when using the three-drug regimen (P log rank = 0.0005): median time to reach this level was 4 weeks and 12 weeks, respectively. No differences were found in HIV-1 RNA elimination rate constants in the first 2 weeks after the initiation of therapy. When the viral load declines were calculated from day 2 onwards, adjusting for differences in pharmacological delay of the drugs used, again no differences in early viral load decline were found between the two regimens. CONCLUSION: With the five drugs used in this study, the median time to reach < 50 HIV-1 RNA copies/ml was 8 weeks shorter than with the three-drug regimen. This finding shows that suppression of viral load in HIV-infection by standard triple-drug therapy can be improved upon.

Adult↗
PubMed1998

[Virological evaluation of treating HIV-infected patients with (combinations of) antiretroviral drugs at the Amsterdam Academic Medical Center, 1996/'97].

OBJECTIVE: First clinical virological evaluation of anti-HIV treatment with HIV reverse transcriptase (RT) and protease inhibitors. DESIGN: Descriptive. SETTING: Academic Medical Centre of the University of Amsterdam, the Netherlands. METHOD: From January 1, 1996, until May 1, 1997, HIV-RNA levels were determined in sequential serum or plasma samples obtained sequentially of 384 patients over a period of 3.1 years on average (minimum 0.5, maximum 10 years). Of these patients 318 had sustained treatment for at least 6 months. The effect on HIV-RNA serum or plasma levels was evaluated in this particular group, of which 224 (70.4%) had been pretreated with antiretroviral drugs (experienced patients) and 94 (29.6%) had not (naive patients). RESULTS: Of the naive patients 8.5% were treated with a combination of two, 89.4% with three and 2.1% with four anti-HIV drugs. Preceding their current treatment, an average of more than two other anti-HIV regimens had been administered to the experienced patients. From 1987 until May 1997 a total of 834 treatments were registered among the 224 patients: 202 mono, 223 double, 340 triple, 60 quadruple and 9 other combination treatments. After six months 84% of the triple combination treatments in the naive patients and 61% in the experienced patients resulted in RNA levels < or = 10(3) copies/ml (p = 0.008). Of 68 patients who failed on treatment 36 (52.9%) showed resistance associated mutations in HIV reverse transcriptase. In 6/43 (14%) of these patients resistance associated mutations in protease were found as well. Genotypic resistance could not always be confirmed phenotypically. CONCLUSION: Our preliminary results indicate that in a majority of cases triple combination treatment including at least one HIV protease inhibitor was successful. Nevertheless, in 16% of the therapy-naive and 39% of the therapy-experienced patients the anti-HIV effect of treatment was insufficient.

Antiviral Agents↗
PubMed1998

Kinetics of CD4+ T cell repopulation of lymphoid tissues after treatment of HIV-1 infection.

Potent combinations of antiretroviral drugs diminish the turnover of CD4+ T lymphocytes productively infected with HIV-1 and reduce the large pool of virions deposited in lymphoid tissue (LT). To determine to what extent suppression of viral replication and reduction in viral antigens in LT might lead correspondingly to repopulation of the immune system, we characterized CD4+ T lymphocyte populations in LT in which we previously had quantitated viral load and turnover of infected cells before and after treatment. We directly measured by quantitative image analysis changes in total CD4+ T cell counts, the CD45RA+ subset, and fractions of proliferating or apoptotic CD4+ T cells. Compared with normal controls, we documented decreased numbers of CD4+ T cells and increased proliferation and apoptosis. After treatment, proliferation returned to normal levels, and total CD4+ T and CD45RA+ cells increased. We discuss the effects of HIV-1 on this subset based on the concept that renewal mechanisms in the adult are operating at full capacity before infection and cannot meet the additional demand imposed by the loss of productively infected cells. The slow increases in the CD45RA+ CD4+ T cells are consistent with the optimistic conclusions that (i) renewal mechanisms have not been damaged irreparably even at relatively advanced stages of infection and (ii) CD4+ T cell populations can be partially restored by control of active replication without eradication of HIV-1.

Adult↗
PubMed1998

Decrease of HIV-1 RNA levels in lymphoid tissue and peripheral blood during treatment with ritonavir, lamivudine and zidovudine. Ritonavir/3TC/ZDV Study Group.

OBJECTIVES: Triple combination treatment of HIV-1 infection using two reverse transcriptase inhibitors and a protease inhibitor can result in significant and sustained decreases in the quantity of viral RNA in peripheral blood. Lymphoid tissue, however, constitutes the major reservoir of HIV in infected patients. Study of the viral burden in these tissues has provided additional insight in the efficacy of antiretroviral treatment. DESIGN: Patients were randomized into two groups in order to study differences in the development of resistance to reverse transcriptase inhibitors. Group I started treatment with all three drugs simultaneously. Group II started with ritonavir monotherapy, aiming at initial reduction in virus production before the addition of lamivudine and zidovudine 3 weeks later. METHODS: Changes in the amount of HIV in plasma and tonsillar lymphoid tissue during 24 weeks of treatment with ritonavir, lamivudine and zidovudine were studied by reverse transcriptase polymerase chain reaction. RESULTS: Thirty-three antiretroviral-naive HIV-infected patients were included for analysis. After 24 weeks, median CD4+ cell count increased by 152 x 10(6)/l and median plasma viral RNA levels decreased by at least 2.87 log10 copies/ml. In 88% of the patients remaining on treatment, plasma RNA levels were below the quantification limit of the assay used (mean, 2.4 log10 copies/ml). The lymphoid tissue viral burden, ranging from 9.16 to 8.52 log10 copies/g at baseline, was markedly reduced with at least 2.1 log10 copies/g by week 24 in the five patients analysed. Eight patients (24%) withdrew because of side-effects. In one patient in group II, ritonavir and lamivudine resistance-associated mutations developed. CONCLUSIONS: Treatment with this triple antiretroviral drug combination produced a durable and strong decrease of HIV-1 RNA burden in both plasma and lymphoid tissue.

Adult↗
PubMed1998

Biphasic kinetics of peripheral blood T cells after triple combination therapy in HIV-1 infection: a composite of redistribution and proliferation.

The origin of CD4+ T cells reappearing in the blood following antiretroviral therapy in human immunodeficiency virus type-1 (HIV-1) infection is still controversial. Here we show, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4+ T-cell numbers reach a plateau. The increase in CD4+ T cells following therapy most likely is a composite of initial redistribution, accompanied by a continuous slow repopulation with newly produced naive T cells.

Anti-HIV Agents↗
PubMed1998

Impact of diarrhoea and faecal incontinence on the daily life of HIV-infected patients.

Diarrhoea in HIV-1 infected persons is an important clinical problem. To improve care and counselling, information about the way, and the extent to which, diarrhoea influences the daily life of these patients can be useful. A cross-sectional descriptive study was performed at the HIV infection clinic of three major hospitals in Amsterdam. A diary, the Coates card system (to determine the relative severity of the symptoms) and an interview were used as outcome measures. Sixty-two patients participated and were classified into four groups: group 1 (minor diarrhoea, n = 26), group 2 (mild diarrhoea, n = 18), group 3 (moderate diarrhoea, n = 7) and group 4 (severe diarrhoea, n = 11). Diarrhoea was considered a very severe symptom in groups 2, 3 and 4. Even mild diarrhoea may have a debilitating impact on the day-to-day life of HIV-infected patients. Faecal incontinence occurs frequently. Patients can worry about their diarrhoea because of lack of information. Patients who do not have diarrhoea according to current definitions of it, consider diarrhoea to be equally problematic as those with (moderate) diarrhoea. More information on prognosis and practical solutions for patients are recommended.

Activities of Daily Living↗
PubMed1998

Effects of protease inhibitors on the course of CMV retinitis in relation to CD4+ lymphocyte responses in HIV+ patients.

AIM: To gain insight into the course of CMV retinitis (CMVR) in AIDS patients receiving protease inhibitors (PI), and to evaluate whether certain patterns of CD4 response are indicative of the clinical outcome and the risk of recurrence. METHODS: 15 consecutive AIDS patients receiving maintenance therapy for CMVR were included in a prospective observational cohort study at the university hospital between July and October 1996. Patients were evaluated for signs of CMVR activity and intraocular inflammation. CMVR recurrence was defined as the primary clinical endpoint. Follow up was performed until July 1997. No patient was lost to follow up. Clinical outcome was related to CD4+ lymphocyte counts, which were monitored every 6 weeks. Highly active antiretroviral treatment regimen including PI was started at study entry. RESULTS: All recurrences (n = 7) were in patients who failed to have a sustained increase in CD4 counts, whereas CMVR remained inactive during a follow up of 42-52 weeks in those who were able permanently to restore their CD4 values to 100 x 10(6)/l or more (n = 5). The remaining three patients died after 12, 16, and 50 weeks, respectively, without recurrences. All relapses of CMVR were seen after 6-16 weeks, and at CD4 counts well below 100 x 10(6)/l. CONCLUSIONS: The beneficial effects of PI treatment correlate with the pattern of CD4 response. Sustained increases in CD4 counts achieved in the first 16 weeks of treatment are associated with a prolonged period of CMVR quiescence. Poor initial response is associated with a high risk of CMVR recurrence.

AIDS-Related Opportunistic Infections↗
PubMed1997

Patterns of T-cell repopulation, virus load reduction, and restoration of T-cell function in HIV-infected persons during therapy with different antiretroviral agents.

The effect of antiretroviral therapy on both T-cell numbers and T-cell function in peripheral blood was studied. CD4+ and CD8+ T-cell numbers, T-cell reactivity to CD3 monoclonal antibodies (mAb), and viral RNA load date were obtained from patients treated for at least 28 weeks with either the HIV-1 protease inhibitor ritonavir, the nonnucleoside HIV-1 reverse transcriptase (RT) inhibitor nevirapine, or the nucleoside-analogue RT inhibitor zidovudine. Compared with both RT inhibitors, treatment with the protease inhibitor ritonavir resulted in the most significant and persistent elevation of CD4+ and CD8+ T-cell counts. However, in vitro T-cell functional improvement was of limited duration in the ritonavir-treated group and was inversely correlated with viral RNA load changes during the entire follow-up period. Thus, despite what can be assumed of responses during RT inhibitor therapy, quantitative responses on therapy did not necessarily correlate with qualitative immunologic responses, as can be seen during treatment with ritonavir. For optimal immune reconstitution, both numeric and functional immunologic improvements are essential. During antiretroviral therapy, measurement of in vitro improvement in immune function will be useful as a correlate for transient drug-induced alteration of immunodeficiency.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Selective inhibition of syncytium-inducing and nonsyncytium-inducing HIV-1 variants in individuals receiving didanosine or zidovudine, respectively.

By studying changes in the clonal composition of HIV-1 populations during the first weeks of zidovudine (ZDV) treatment before the development of ZDV resistance-conferring mutations, we demonstrated previously a selective inhibition of nonsyncytium-inducing (NSI) HIV-1, even when present as coexisting population in individuals also harboring syncytium-inducing (SI) HIV-1. In this study, we observed the opposite in individuals receiving didanosine (ddI) treatment. In these individuals (n = 7) a median -0.98 log change (range -1.55-0.08) in infectious cellular SI load was observed, whereas the coexisting NSI load was only minimally affected (median -0.15 log, range -1.27-0.50; P = 0.03). The virus phenotype-dependent treatment responses were independent of the clonal composition of HIV-1 populations at baseline. Individuals treated with a combination of ZDV and ddI revealed an equal decline of both NSI and SI infectious cellular load (n = 4; NSI: median -1.55 log, range -2.19 to -1.45; SI: median -1.47 log, range -1.81 to -0.86; P = 0.56). To test the hypothesis that the previously reported optimal activation of ZDV and ddI in activated and resting T cells, respectively, in combination with the differential T cell tropism of NSI and SI HIV-1 is the basis for the observed virus phenotype specific efficacy of nucleoside analogs, we studied the effect of treatment with a protease inhibitor that does not require intracellular activation. Individuals receiving ritonavir (n = 4) indeed showed equal declines in NSI and SI infectious cellular load (NSI: median -2.37 log, range -2.59 to -2.16; SI: median -2.82 log, range -3.14 to -2.50; P = 0.25). Our data suggest HIV-1 phenotype as an additional parameter in the design of optimal treatment regimens.

Animals↗
PubMed1997

Kinetics of response in lymphoid tissues to antiretroviral therapy of HIV-1 infection.

In lymphoid tissue, where human immunodeficiency virus-type 1 (HIV-1) is produced and stored, three-drug treatment with viral protease and reverse transcriptase inhibitors markedly reduced viral burden. This was shown by in situ hybridization and computerized quantitative analysis of serial tonsil biopsies from previously untreated adults. The frequency of productive mononuclear cells (MNCs) initially diminished with a half-life of about 1 day. Surprisingly, the amount of HIV-1 RNA in virus trapped on follicular dendritic cells (FDCs) decreased almost as quickly. After 24 weeks, MNCs with very few copies of HIV-1 RNA per cell were still detectable, as was proviral DNA; however, the amount of FDC-associated virus decreased by >/=3.4 log units. Thus, 6 months of potent therapy controlled active replication and cleared >99.9 percent of virus from the secondary lymphoid tissue reservoir.

Adult↗
PubMed1997

Prevalence of Campylobacter-associated diarrhea among patients infected with human immunodeficiency virus.

We performed a cross-sectional study at an outpatient AIDS clinic to assess the prevalence of Campylobacter species in stool specimens from 201 consecutive patients infected with human immunodeficiency virus (HIV). We characterized campylobacters phenotypically and genetically by using primers for the group of common species (i.e., C. jejuni, C. coli, C. lari, and C. upsaliensis) and for most individual uncommon species. We performed cultures with use of a membrane filter technique on nonselective blood agar and found that Campylobacter species were the most frequent enteropathogenic bacteria: the organisms were recovered from 7 (16%) of 43 patients with diarrhea and 5 (3%) of 158 patients without diarrhea (P = .001). We isolated only one campylobacter with use of conventional culture techniques on selective media. Phenotypic characterization of 10 campylobacter strains resulted in the misidentification of four isolates. C. upsaliensis was the most frequently isolated species, followed by C. jejuni and C. coli. Two strains could not be identified with the available primers. Two of 12 Campylobacter strains were resistant to erythromycin, and two were resistant to ciprofloxacin. We conclude that Campylobacter species other than C. jejuni can frequently be detected in the stools of HIV-infected patients and that these organisms could be associated with diarrhea.

Adult↗
PubMed1997

Additive or sequential nucleoside analogue therapy compared with continued zidovudine monotherapy in human immunodeficiency virus-infected patients with advanced disease does not prolong survival: an observational study.

To study the effect of sequential or additive use of zalcitabine or didanosine on survival in 308 human immunodeficiency virus-infected patients with advanced disease treated with zidovudine, an observational study using time-dependent Cox proportional hazards models was done. Changing to sequential or additive therapy was based on deterioration of a patient's health status, a significant drop in CD4 cell count, or intolerance for zidovudine. The median CD4 cell count at baseline was 110 x 10(6)/L; 42% of patients had AIDS. The median count before a change in therapy was 50 x 10(6)/L. Additive or sequential treatment was associated with an increased risk for death (relative hazard, 1.59; 95% confidence interval [CI], 1.01-2.49; and 1.58; 95% CI, 1.10-2.37, respectively). Adjustment of the models for prognostic factors failed to substantially affect this observation. Possibly the lack of benefit in this study is because patients switched therapy at advanced stages, whereas the switch may be more effective in early disease.

Adult↗
PubMed1997

High-dose interferon-alpha2a exerts potent activity against human immunodeficiency virus type 1 not associated with antitumor activity in subjects with Kaposi's sarcoma.

Anti-human immunodeficiency virus type 1 (HIV-1) activity was assessed in HIV-1-infected homosexual and bisexual men receiving 18-36 MIU/day of recombinant interferon (IFN)-alpha2a for Kaposi's sarcoma (KS). The median baseline HIV-1 RNA level was 4.99 log10 copies/mL. Seventeen subjects (68%) showed an RNA decline > or = .5 log10/mL, with a maximum at week 4 (median decline = 1.91, range = 3.64-1.15; P = .0007), after which RNA levels stabilized. Eight subjects (32%) with lower median initial CD4+ T cell counts (60 vs. 350 x 10(6)/L; P = .01) did not show RNA responses. Neither RNA nor KS responses were negatively affected by IFN-alpha2a dose modifications. Anti-HIV responses of KS responders (n = 15) and nonresponders (n = 10) did not differ. High-dose IFN-alpha can exert potent anti-HIV activity that is not associated with anti-KS activity.

AIDS-Related Opportunistic Infections↗
PubMed1997

Results of long-term follow-up of HIV-infected patients treated with lamivudine monotherapy, followed by a combination of lamivudine and zidovudine.

The objective of this study was to determine the efficacy and safety of adding zidovudine to continuous treatment with lamivudine in symptomatic human immunodeficiency virus type 1 (HIV-1)-infected patients. Forty patients were monitored throughout lamivudine monotherapy and subsequent combination therapy with lamivudine and zidovudine, which was initiated because of disease progression, declining CD4 cell counts or prolonged use of lamivudine. Eleven of these patients had been treated with zidovudine before the start of the study. The median CD4 cell count at the start of lamivudine monotherapy was 200 x 10(6) cells/l. After a median interval of 69 weeks (range 23-102 weeks), the median CD4 cell count had dropped to 110 x 10(6) cells/l. Initial improvements in all laboratory markers for antiretroviral efficacy were observed after the addition of zidovudine. The median CD4 cell count remained 18% above baseline after 48 weeks of treatment with lamivudine and zidovudine, however plasma HTV-1 RNA load and CD4 cell counts returned towards baseline during prolonged treatment in most patients. The combination was well tolerated, although anaemia was observed in nine patients. Repeated measures analysis of variance suggested a superior effect of lamivudine monotherapy in patients who had previously used zidovudine. In conclusion, zidovudine was found to be effective in patients who have been treated with lamivudine. The study stresses the need to further define the mechanisms underlying this prolonged antiviral effect.

Anti-HIV Agents↗